EN 1355-1996 en Determination of Creep Strains under Compression of Autoclaved Aerated Concrete or Lightweight Aggregate Concrete with Open Structure《高压多孔混凝土或开放结构轻集料混凝土受压蠕动变形的测定》.pdf

《EN 1355-1996 en Determination of Creep Strains under Compression of Autoclaved Aerated Concrete or Lightweight Aggregate Concrete with Open Structure《高压多孔混凝土或开放结构轻集料混凝土受压蠕动变形的测定》.pdf》由会员分享，可在线阅读，更多相关《EN 1355-1996 en Determination of Creep Strains under Compression of Autoclaved Aerated Concrete or Lightweight Aggregate Concrete with Open Structure《高压多孔混凝土或开放结构轻集料混凝土受压蠕动变形的测定》.pdf（13页珍藏版）》请在麦多课文档分享上搜索。

1、STD-BSI BS EN 1355-ENGL 1997 W lbZLIbb9 Ob?i70qq 780 BRITISH STANDARD Determination of creep strains under compression of autoclaved aerated concrete or lightweight aggregate concrete with open structure The European Standard EN 1355 : 1996 has the status of a British Standard ICs 91.100.30 NO COPYI

2、NG WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW BS EN 1355 : 1997 STD-BSI BS EN 1355-ENGL 1797 Lb24bb7 Ob117045 bL7 9 AmdNo. Date BS EN 1355 : 1997 Textaected Committees responsible for this British Standard The preparation of this British standard was entrusted to Technid Committee M

3、23, Prefabricated concrete and lightweight aggregate concrete with open structure, upon which the following bodies were represented Aggregate Concrete Block Association Autoclaved Aerated Concrete Association British Masonry Society British Precast Concrete Fededon Ltd. Department of the Environment

4、 (Building Research Establishment) Institution of Structurai Engineers Lod Authority Organizations This British Standard, having been prepared under the direction of the Sector Board for Buiiding and Civil Engineering, was published under the authority of the Standards Board and comes into effect on

5、 15 October 1997 O BSI 1997 The foiiowing BSI references relate to the work on this standard: Committee reference BI523 Draft for comment 9Wl0407 DC ISBN O 680 27477 2 STD-BSI BS EN L355-ENGL 1997 Lb24bb7 Ob470Llb 553 m BS EN 1355 : 1997 Contents Committees responsible National foreword page Inside

6、front cover ll Foreword 2 Text of EN 1355 3 O BSI 1997 i - STD-BSI BS EN 1355-ENGL 1977 lb2Libb7 b47047 49T = BS EN 1366 : 1997 National foreword This British Standard has been prepared under the direction of Technid Committee B/523 and is the English language version of EN 1355 : 1996 Determination

7、 of creep srnulins under compes.sion of autoclaved aerated concrete cur lightweight aggregate concrete with open stwture, published by the European Committee for StanarWon (CEN). Cross-references EN 678 : 1993 EN 679 : 1993 EN 992 : 1995 EN 1354: 1996 Publication referred to Corresponding British St

8、andard BS EN 678 : 1994 Determination of th dry density of autoclaved mted concrete BS EN 679 : 1994 Determination of compressive strength of autoclaved mted concrete BS EN 992 : 1996 Determination of dry density of lightweight aggregate concrete with open structure BS EN 1354 : 1997 Determination o

9、f compressive strength of lightweight aggregate concrete with open structure Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, the EN title page, pages 2 to 8, a

10、n inside back cover and a back cover. ii O BSI 1997 STD-BSI BS EN L355-ENGL EXJROPIWN STANDARD NO= EUR0PEE”E EXJROP- NORM 1997 = Lb24bb9 b47048 32b m EN 1355 December 1996 ICs 91.100.30 DesCnptOrs: Concrete, cellular concrete, aggregates, mechanical tests, compression tests, creep tests, determinati

11、on, creep strength J3ngbh version Deteeon of creep shins under compresion of ;uxtoclaved aerated concrete or lightweight mgak concrete with open ma Dtemimtion du fluage en compression du bton cduiaire autoclav et du btm de grandah lgers structure ouverte Bestimmung der Kriechverformungen unter Druck

12、beanspruchung von dampfgehrtetem Porenbebn und von haufwerksporigem hichtbebn This European Standard was approved by CEN on 199 b) Gaip, capable of reading the dimensions of the test specimens to an accuracy of 0,l mm; c) A straight-ege, feeler gauges (0,l mm for AAC, 0,5 mm for LAC, and 1,0 mm for

13、both) and a square; d) A balance, capable of determining the mass of the test specimens to an accuracy of 0,l oh e) Equalizing layers of sofi fibmboard (only in the case of LAC), with a thickness of (12 f 2) mm and a density of (250 to 400) kg/m3 to be inserted between the loadbearing surfaces of th

14、e test specimens and the platens of the compression testing machine (not required in the case of levelling the loadbearing surfaces by grinding or capping); f) A loading fmm, capable of applying and maintaining the required compressive load on the test specimen) for the required period of time (in g

15、eneral at least one year), despite any length change of the test specimen(s) (see note 1). The header plates of the loading frame shall have sufficient stiffness, and their bearing surface shall not depart from a plane by more than 0,l mm per 100 mm. In any loading frame several test specimens may b

16、e stacked for simultaneous loading. Means shaU be provided for measuring the load to the nearest 3 % of the total applied load. This may be a permanently instailed pressure gauge or a hydraulic jack or load cell inserted temporarily in the frame when the load is applied or dusted When a hydraulic lo

17、ad-maintaining element is used, several frames may be loaded simultaneousiy through a central hydraulic pressureregdating unit When springs are used, care shall be taken to provide a spherical seated head, or a ball joint and end plates rigid enough to ensure uniform 10- of the test specimens. g) A

18、measuring device, for the detennjnation of the longitudinal length changes (strains) of the test specimens. The apparatus may be portable or attached (see note 2). If portable apparatus is used, gauge points shall be attached to the test specimen in a positive manner which is normaUy done by glueing

19、 with rapid hardening giue. The gauge length shall be not less than 100 mm. The gauge points shali be provided accurately on the longitudinal axes of the four longitudinai surfaces of the prismatic test specimens, and they shall be attached equidistant from the ends, the distance from the aacent end

20、 being not less than 50 mm. l) A European Standard for prefabricated reinforced Components of autoclaved aerated concrete is in preparation at CEN. O BSI 1997 Page 4 EN 1366 : 1996 The device shall be capable of measuring Strains to the nearest 10 x 10 -6 (o,o dm) for at least one year without chang

21、e in calibration. h) a morn, capable of maintaining a temperature of (20 * 2) “C and a relative humidity of (60 5 5) “m; j) a ventated drying oven, capable of maintaining a temperature of (105 1: 5) “C (see note 3). NOTE 1. A usual he consists of header plates bearing on the ends of the loaded test

22、specimens, a load maintaining element that may be either a spring or a hydraulic capsule or ram, connected wih a cylinder of high pressure nitrogen and a hydraulic pressure-regulating unit, and threaded rods to take the reactions of the loaded system. NOTE 2. Systems in which the varying length chan

23、ges or strains are compared with a constant-length standard bar are considered most reliable. NOTE 3. In addition, a ventilated drying oven capable of maintaining a temperature of (40 to 60)“C can be helpful for conditioning of test specimens. 5 Est specimens 6.1 Sample The sample for the preparatio

24、n of the test specimens (usually at least one prefabricated component) shall be taken in such a manner that it is representative of the product to be investigated. 6.2 Shape and size of test specimens The reference test specimens shall be prisms with a squarec- on of 100 mm X 100 mm and a height of

25、300 mm. lst specimens of other sizes or shape may be used, provided that the correlation to the resuits of tests on the above reference test specimens is established. 6.3 Number of test specimens At least two test specimens for determimion of creep (creep specimens) and two control specimens for det

26、ermination of shrinkage shall be prepared from the centrai part of the component (see ngUre 1). 6.4 Preparation of test specimens The specimens shall be cut not less than 2 d after autoclaving or casting, respectively The dust or the sluny of the process shall be removed They shall be taken in such

27、a way that their longitudinai axis is: - in the case of AAC - in the case of LAC perpendicular to the rise of the mass during the manufacture; in the piane of the compression force acting in the component when used in the structure. The specimens shal contain no reinforcing bars within the gauge len

28、gth. (If unavoidable, bars which are perpendicular to the longitudinal axis may be accepted in exceptional cases. This shall be mentioned in the test report.) The loadbearing surfaces of the creep specimens shall be plane, parallel to each other and perpendicular to the longitujnal surfaces of the s

29、pecimens. Planeness of loadbearing surfaces sha be checked across the two diagonals using a straightedge and, if nece-, a feeler gauge. Deviations exceeding 0,2 mm shall be adjusted by cutting andor grindmg or by capping. In the case of LAC, deviations up to 0,s mm may be tolerated, provided that eq

30、ualizing layers of soft fibreboard according to 4e) are used. Deviations from planeness of the other surfaces shall not exceed 1 mm. The angle between the loadbearing surfaces and the adjacent longitudid surfaces of the creep specimens shall not daiate from a right angle by more than 1 m per 100 m.

31、This shall be checked dong both orthogonal middle axes of the loadbeakg surfaces by means of a square and a 1 mm-feeler gauge or similar instrument. Larger deviations shall be corrected by cutting or grinding. Direction of rise (for AAC)- Figure 1. Sampling scheme O BSI 1997 STD-BSI BS EN 1355-ENGL

32、1997 1624bb9 0b1i7052 857 9 6.6 Measurement of test specimens The dimensions of the creep specimens and control specimens shall be measured to an accuracy of 0,l nun, using callipers. Length and width of the cross-sectional area, Ac, shall be measured at mid height at two opposite longitudinal sides

33、. The cross-seCtiona area shall be calculated using the mean values of the results of the measurements. The height of the specimens shall be measured in the middle of two opposite longitudinal sides. The volume Vof the specimen shall be calculated by multiplying Ac by the mean value of the results o

34、f the height measurements. 6.6 Conditioning of specimens The test specimens shall be conditioned at a temperature not exceeding 60 “C unti their mass related moisture content is (6 f 2) W This may be estimated by comparing their moist density with the dry density determined in accordance with EN 678

35、 for AAC or with EN 992 for LAC, respectively, on companion specimens exh.acted from the same area of the same component (see note). After reaching the specified moisture content, the test specimens shall be stored, protected against moisture changes, for at least 72 h prior to the test at (20 f 2)

36、“C for ensuring uniform moisture distribution withjn the test specimen and thtrmal equiibrium with the temperature in the iaborahry During the creep test the test specimens shail be exposed to the surrounding air with a temperature of (20 f 2) “C and a relative humidity of (60 f 5) %. Conditions oth

37、er than the above reference conditions may be chosen if required. This shall be indicated in the test report. The actual moisture content of the specimens at the beginning and at the end of the creep test and the dry density shall be determined For this purpose the specimens shall be weighed prior t

38、o the creep test, before applying any devices for measurement of deformations and after completion of the creep test, after removal of gauge plugs etc. Fh-diy, they shall be dried to constant mass at (105 f 5) “C (see clause 7). if the removal of the adhesive xed gauge plugs is likely to remove conc

39、rete, the initiai mass of the test specimen with and without gauge plugs shall be taken, and the appropriate correction shall be made in the calculations. NOTE. The expected moisture content of a test specimen may be calculated according to equation (1): Page 5 EN 1355 : 1996 where Pm,exp Phum,t is

40、the expected mass related moisture content, in per cent; = ?nh, / V is the moist density of the test specimen, calculated by dividing its moist mass ?nhm by its volume V determined according to 6.6, in kilograms per cubic metre; is the dry density of companion specimens determined according to EN 67

41、8 (for AAC) or EN 992 (for LAC), in kograms per cubic metre. Pcomp 6 Creep test 6.1 Age at loading and duration of sustained load In the case of AAC the age at loading is optional. In the case of LAC the creep specimens shall be loaded at an age of 28 d, if not specified otherwise. The applied load

42、shall be sustained constant, in general for a period of at least 1 a It may be necessary to continue the test for a longer period, if the deformations are stiil increasing at a considerable rate at that time. 6.2 Loading details Immediately before loading the creep specimens the compressive strength

43、 of the concrete shall be determined, according to EN 679 for AAC or EN 1354 for LAC, respectively, on test specimens taken from the same sample. At the time creep specimens are placed in the loading frame, the end faces of the control specimens for shnnkage measurement shall be covered in order to

44、provide the same drymg conditions as for the creep specimens. The creep specimens shall be placed in the loading frame taking care in aiigning the specimens to avoid excenttic loading. In the case of LAC, provided that the creep specimens have not been ground or capped and the deviations from planen

45、ess of the loadbearing surfaces exceed 0,2 mm, equalizing layers of soft fibreboard, as specified in 4e), shall be inserted between the loadbearing faces of the creep specimens and the header plates of the loadrig he, and also between the individual creep specimens, if severai specimens are stacked

46、in one loading frame. After proper aiigning the creep specimens (see note) the load shall be applied at the specified intensity which is usually chosen such that the resulting stress is one third of the strength at the age of loading, but not more than 40 % of that value. O BSI 1997 STD-BSI BS EN 13

47、55-ENGL 1777 lb2Llbb7 Ob97053 793 W Page 6 EN 1355 : 1996 The duration of loading process should be as short as practicable and shall in no case exceed 15 min. Strain readings shall be taken immediately before and after loading, 2 h to 6h later, after 1 d and then at appropriate intervals, in genera

48、l until at 1 a, so that the curve representing the development of strains with time can be reliably recorded. Before each strain measurement, the load shall be controlled and adjusted, if deviating by more than 2 % from the correct value. Strain readlligs on the control specimens shall be taken on t

49、he same schedule as for the loaded specimens. NOTE. For control of centric loading it may be helpful to apply a smaii preload not exceeding 25 % of the nal sustained load and to note the strain variation around each creep specimen, after which, if necessary, the load may be removed and the specimens realigned for greater strain uniformity. Strain distribution may also be influenced by tightening or loosening the nuts on the threaded reaction rods if this type of loading frame is used (see note 1 in clause 4). If possible, the strain variation arou